Conventionally, a treatment has been performed, in which an incision is formed in ocular tissue such as the cornea (sclera) and an anterior capsule portion of an eyeball, an intracapsular crystalline lens is extracted and removed through the incision, and then an intraocular lens that replaces a crystalline lens is inserted into the eye through the incision to be disposed in the anterior capsule.
The intraocular lens having a power consistent with a diopter scale of a patient is inserted into the eyeball of the patient by the surgery. If the diopter scale of the patient is not consistent with the power of the inserted intraocular lens, eyesight of the patient may not be recovered sufficiently even after the surgery, therefore, it is necessary to arrange the intraocular lenses having standards with different powers (focal distance) between +30D and +6D, for example, and to select the most appropriate one. In addition, with respect to the arranged intraocular lenses of all of the standards, the aberration of the whole eyeball after the insertion of the intraocular lens is required to be set to a desired value.
Here, the following relation is satisfied between the aberration of the whole eyeball, the aberration of the cornea and the anterior chamber portion, and the aberration of the crystalline lens and posterior chamber portion.Aberration of crystalline lens and posterior chamber portion=Aberration of whole eyeball−Aberration of cornea and anterior chamber portion  (1)
Further, in an eyeball, when the crystalline lens is removed, and then the intraocular lens instead of the crystalline lens is inserted into the eyeball, similarly, the following relation is satisfied between the aberration of the whole eyeball, the aberration of the cornea and the anterior chamber portion, and the aberration of the intraocular lens.Aberration of intraocular lens=Aberration of whole eyeball−Aberration of cornea and anterior chamber portion  (2)
Upon designing the intraocular lens, a target value of the aberration of the intraocular lens is determined on the basis of formula (2) and a shape of the intraocular lens is determined so as to be the determined aberration, (furthermore, the aberration in the above formula represents a wavefront aberration expressed by Zernike polynomials). In the related art, however, with respect to the aberration in each term of formula (2), a numerical value of a case where parallel light enters each element has been used. Meanwhile, in an actual usage environment, convergent light due to the cornea and the anterior chamber portion enters the intraocular lens. Accordingly, when the aberration in the whole eyeball of a patient is measured after the intraocular lens designed by the method of the related art is inserted into the eyeball, there has been a case where the value of the aberration deviates from a set value.